Process of treating clay.



PA'I'ENTED JAN. 9, 1905.

D. B. WILLIAMS. PROCESS OF TREATING CLAYS. APPLICATION FILED JULY2.1903, RENEWED JULY 18,1904.

Afz omey llurTnn STATES Patented January 3, 1905.

PATENT Tricia,

DICK B. WILLIAMS, OF OONNELLSVILLE, PENNSYLVANIA, ASSIGNOR OF ONE-HALFTO JOSEPH R. STAUFFER, OF SCOTTDALE, PENNSYLVANIA.

PROCESS OF TREATING CLAY.

SPECIFICATION forming part of Letters Patent No. 779,195, dated January3, 1905.

Application filed July 2, 1903. Renewed July 18, 1904. Serial No.217,120.

To all whom, it may concern:

Be it known that LDIoK B. WILLIAMs,a citi- Zen of the United States,residing at Connellsville, in the county of Fayette and State ofPennsylvania, have invented certain new and useful Improvements inProcesses of Treating Clays, of which the following is a specification.

This invention relates to an improved process for treating clays toproduce a highly indurated and refractory product possessing greatutility for a variety of commercial purposes and especially adaptablefor fire-brick, refractory linings, crucibles, and other articles whichare subjected to very high temperatures.

It has been developed by experiment and observation that the specificprocess contemplated by the present invention effects peculiar resultsupon clay products of the pure and mixed grades and also possesses thepractical and important advantage of converting the inferior andinfrequently-used grades of clay, such as blue clay, into a substancecapable of withstanding almost an indefinite degree of heat withoutlosing its form or general characteristics, thus rendering the saidsubstance available for the manufacture of articles which are intendedto withstand intense heats.

The invention also has in view a process providing for the production ofa new indurated or refractory product having all of the properties ofwhat is ordinarily known as carborundum, with a distinct advantage overthe latter of being a solid compact substance which can be produced inany desired form and at a singlefiringgthus effecting great economy intime.

It is well known that pure and mixed clays have been treated with carbonin divers ways to produce an indurated and refractory product, and it isalso well known that various combinations of carbon, silica, and oxygenhave been effected with the same end in view. The manufacture ofcarborundum is an exemplification of the prior art in this direction,which substance results from the reaction between carbon and silica, thelatter being conveniently supplied in the form of sand. These the same.

known processes,however,involve the thought 5 0 of mixing together thesand and carbon or clay and carbon or other materials and effecting afusing together of the mixture to produce the resultant hard substanceor product.

In the production of these and similar products heretofore recourse hasbeen made to electric furnaces in which the mixed charge is introducedso as to lie Within the Zone of the current passing betweenoppositely-located conductors, and it is only the material within theZone of the current which undergoes the chemical change incident to theheating up of Also in some methods heretofore practiced the object hasbeen to provide compounds containing silicon, oxygen, and carbon inchemical combination; but the present invention involves a specifictreatment of the clay material that eliminates to a minimum the presenceor union of oxygen from extraneous sources and also absolutely avoidingthe mixing of the carbon with the clay material which undergoes theindurating or hardening action. It has also been found by experimentthat the peculiar product formed by this process can be best produced bythe utili- 7 5 Zation of coke, which in spite of its porosity conductsheat veryreadily and most eflectively evolves the monoxid of carbon,which is depended upon exclusively to secure the desired results. Hencethe important and dis- 8o tinctive feature of the process forming thesubject-matter of the present invention resides in the fact that theform of carbon employed does not itself become any part of the body ofclay material; but the result accomplished 8 5 is entirely through theaction of the cokegases (principally carbon monoxid) on the clay.

' The apparatus employed in carrying out the invention may obviously beof any suitable 9 character in which the essential conditions of theprocess may be preserved. So for illustrative purposes there is shown inthe drawings a diagrammatic figure illustrative of an ordinary form ofcrucible-furnace presenting perfeet conditions for the process.

Referring more specifically to the process, the first step therein is tomold the clay in any desired shape or form according to the particulararticle that is to be madethat is, the final shape is given to the claymaterial in the firstinstance,and,as previously explained, this claymaterial may be pure clay or amixture of clay and mica or clay andmica-schist, according to the purpose for which the product is intended,although in all instances the molded form to be treated may be properlysaid to be of clay material. In fact, the invention is of specialimportance in treating pure clay, such as the inferior blue clay, whichis converted into a high-grade useful product.

After the clay or clay material is molded in the desired shape or formthe same is thoroughly dried and the molded form (designated by theletter A in the drawing) is placed in a converting-chamber B, whichcontains a body of coke C in an amorphous condition that is, ground orpulverized-so as to compactly fill the chamberB and especially for thepurpose of compactly enveloping the molded clay forms A. In setting upthe apparatus a quantity of the amorphous coke C is placed in thechamber B, the molded clay form introduced, and then completely coveredwith the ground or amorphous coke C, so that the latter forms a compactcarbon envelop for the clay form. The converting-chamber B maybeconveniently, as illustrated, in the form of an ordinary crucible, andafter the introduction of the clay forms and the embedding thereof inthe amorphous coke C the lid D of the crucible is placed in the topthereof, and the latter is next completely surrounded at the top,bottom, and sides by a fuel envelop or covering of the ordinary brokenor fuel coke E. This fuel envelop or covering E preferably completelyfills the fire-cham ber F of a closed type of furnace G and constitutesa perfect coke seal for the converting-chamber or crucible B andpositively prevents oxygen entering into the converter or crucible Bfrom the outside thereof. After thus arranging the molded forms the fuelis fired and the firing continued for about three hours, which hasordinarily been found sufiicient to completely convert the molded clayforms into the peculiar indurated and refractory product contemplated bythe invention.

I have not been able to determine with defi niteness from the results ofmy experiments the exact chemical action which takes place by subjectingthe molded clay forms to treatment in a highly-heated sealed chamberwhile completely enveloped in a body of amorphous coke; but by reason ofthe complete exclusion of oxygen from extraneous sources the clay bodyis converted into a dark hard substance exclusively through the actionof the cokegases. The principal indurating-gas evolved by this processis carbon monoxid, sometimes termed carbon protoxid. This gas is wellknown for its importance in many metallurgical operations on account ofthe power it or cover thereof, so that there is no tendency of themonoxid within the converting-chamber or crucible to be converted intothe dioxid at or about the lid, which has been found to occur when theconverting-chamber or crucible B was heated in an open furnace and withthe lid unsecured. Under such conditions, which have been experimentedwith at large, it has been found that the product produced is veryinferior and does not possess either the appearance, characteristics, orproperties of that produced by heating the molded form in a sealedchamber containing amorphous coke and itself surrounded by an envelop offuelcoke. Each and all of these conditions are regarded as important tosecure the product in its best form. In further explanation of thecharacteristics of the product treated by the process explained itshould be stated that the clay when taken from the furnace has lost allresemblance to its former condition. It will stand any known heat, isabsolutely unaffected by acids or alkalies, is harder than the hardeststone, as it cannot be cut down with an emery-wheel, while, on the otherhand, being of such hardness as to cut glass better than a diamond. Asalready indicated, it has all the properties of carborundum, while beingmore quickly made and more readily produced in any desired form.

The ordinary usages of the product are many. It possesses specialutility as a firebrick, as metal will not slag to it, and its qualitiesof endurance are infinitely greater, and fire-brick can be produced fromthis product with much greater economy than now prevails on account ofthe shortness of time required to produce the same. This is also ofimportance in using the product for making crucibles. It has also beenfound to make an excellent oil-stone without wear. As anartificial-stone product it can be used in any way, and it has beenfound that by regulating the grain or grade of the clay or mixtureitbecomes apractical and almost indestructible medium for the purpose ofgrinding for such purposes as grindstones and emery-wheels are now used.

As a part of the process it should be further explained that during thetreatment the amorphous coke reachesa high degree of incandescence andmaintains such incandescence, yet without mixing with or adheringmaterial, then embedding the molded form to the clay form in theslightest degree, thus evidencing the fact that the action upon the clayform results exclusively from the cokegas.

From the foregoing it is thought that the essential features of theprocess and the product produced thereby will be apparent withoutfurther description.

While the exact chemical composition of the product has not yet beendefinitely determined, the experimental analyses so far made show thatthe same is markedly deficient in carbons.

Having thus described the invention, what is claimed, and desired to besecured by Letters Patent, is

1. A process for treating clays, which consists in subjectinga moldednatural clay form to the action of an incandescent body of amorphouscarbon while enveloping the form and confined in a sealed chamber.

2. A process for treating clays, which consists in subjecting a driedmolded natural clay form to the action of an incandescent envelop ofamorphous coke surrounding the form and confined in a sealed chamber.

3. A process for treating clays which consists in first molding anddrying natural clay material, then embedding the molded form in anenvelop of amorphous coke confined in a closed chamber,and finallyfiring said closed chamber within a closed furnace to bring the envelopof amorphous coke to an incandescent condition.

4. A process for treating clays which consists in first molding anddrying natural clay in an envelop of amorphous coke sealed within aclosed chamber, completely surrounding the sealed chamber with anenvelop of fuel-coke and finally firing the latter to bring the confinedamorphous coke to an incandescent condition and maintaining it in suchcon dition until the clay form has been converted into the hardenedproduct.

5. An indurated clay product consisting of a body of natural claymaterial whose constituent elements are changed by chemical combinationthrough the action of coke-gas while the material is held in acompactincandescent envelop of amorphous carbon.

6. A process for treating clays which consists in subjecting a naturalclay, while sealed from extraneous sources of oxygen, to the exclusiveaction of the gas evolved from a heated body of carbon.

7. A process for treating claysv which consists in subjecting a driednatural clay body to the action of gas from an incandescent body of cokein physical contact with the clay and covering the same.

8. An indurated clay product consisting of a body of natural clay whoseconstituent ele- DICK B. WVILLIAMS.

Witnesses H. A. CROW, MARIE HoUoK.

